Touch blend smooth surface switch assembly

ABSTRACT

A touch button control system for controlling the speed and functioning of a universal motor in an automatic blender is disclosed. The touch button system features a switch assembly for controlling motor speed, including a smooth surface, extremely flexible, indicia-bearing panel or cover plate which is contacted by the user so as to close selectively a plurality of switch contacts, thereby effectuating predetermined motor speeds.

United States Patent Richard et al.

[451 Sept. 23, 1975 TOUCH BLEND SMOOTH SURFACE SWITCH ASSEMBLYInventors: Carl E. Richard, Enfield', Richard H. Seager, Manchester,both of Conn.

General Signal Corporation, Rochester, NY.

Filed: Mar. 25, 1974 Appl. No.: 454,631

Assignee:

US. Cl 200/5 A; 200/333; 235/145 R;

318/305; 340/365 S; 200/302 Int. C1. H01H 13/04 Field of Search 235/145R; 179/90 K;

74/483 PB; 317/112; 318/305, 351; 307/119; 200/5 E, 5 EA, 5 A, DIG. 25,46, 159.8, 160, 243, 250, 296, 302, 333, 340; 340/365 S References CitedUNITED STATES PATENTS 3,693,775 9/1972 Brooks 200/46 3,699,294 10/1972Sudduth 200/243 3,777,222 12/1973 Harris 200/46 3,818,153 6/1974 Arvai200/5 A Primary ExaminerGerald P. Tolin Attorney, Agent, or Firm--MiltonE. Kleinman; Harold S. Wynn; John F. Ohlandt [5 7] ABSTRACT 10 Claims, 5Drawing Figures Sheet 1 of 3 Sept. 23,1975

US Patent khan: Etta hkwih lnaxu AIM 3 Muza O 0255 5-2 mismu mozu 32:2

0 O O O O MGE US Patent S ept. 23,1975 Sheet 3 of3 3,908,100

MGR

TOUCH BLEND SMOOTH SURFACE SWITCH ASSEIVIBLY BACKGROUND, OBJECTS ANDSUMMARY OF THE INVENTION This invention relates to a switch assembly andmore particularly to a switch assembly adapted to control a universalmotor in respect to selection of the speeds of the motor so as toprovide selected operations for a blender device.

There has appeared on the market during the past decade or so a greatvariety of automatic blenders which are designed to offer a selection offunctions such as chopping, grinding, liquefying, etc. This variety offunctions is enabled by reason of the fine degree of control that can beexercised over the speed of a blender motor. Typically, such finecontrol in discrete steps is effectuated by a push-button array at thefront panel of the blender. For an example of such blender construction,reference may be made to U.S. Pat. No. 3,550,657 to Swanke. The blenderdevice described in the Swanke patent is provided with a plurality ofpushbuttons which are operable effectively to control combinations ofswitches in such a way to select discrete speeds for the blender motorover a wide range. The push-buttons are mechanically interlocked; thatis to say, only one push-button can be pushed in at a given time so asto select a particular speed for the blender motor. Moreover. theselected push-button remains in until another choice of speed has beenmade.

A recent refinement or improvement which has been made in push-buttoncontrol is that disclosed in co pending U.S. Pat. application Ser. No.380,416, now U.S. Pat. No. 3,833,845 which application is assigned tothe assignee of the present application. The invention of the aforesaidcopending application achieves fine control of the motor speed by theuse of simple touch buttons, that is, control elements which elimi natecomplicated, mechanically interrelated parts and provide a fairly simplemovable contact which makes only momentary contact with a fixed contactor contacts.

The present invention has for its primary object to provide a uniqueswitching assembly that is especially adapted for utilization with thetouch button control system of the aforesaid copending application, butwhich is nevertheless applicable to other types or kinds of blenderdevices or to the control systems associated therewith.

Yet another object of the present invention is to improve upon touchbutton control systems by affording the user great ease in themanipulation of the control means, i.e. the touch buttons which are usedto select motor speeds for a blender or the like.

Yet another object is to enhance the ease with which the console of theblender may be cleaned by the user: thus, rather than an upstandingarray of push buttons at such console, around which it is difficult toremove the dust and grime that tend to accumulate, there is simplypresented a smooth surface panel or cover plate. This cover plateisextremely flexible and resilient, although strong and durable. Also, thecover plate is indicia-bearing; that is, it permanently and plainlydisplays the various functions to be realized by actuation; that is, bytouching the particular areas at which the indicia are located, therebyto produce selection of the proper motor speed to achieve that function.

' BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view of a blenderdevice in which the switch assembly of the present invention is shownincorporated, but prior to inclusion of the cover plate therefor.

FIG. 2 is an elevational view in section of the blender device.

FIG. 3 is a view of the indicia-bearing cover plate of the switchassembly of the present invention.

FIG. 4 is an enlarged sectional view of one of the typical touch buttonsutilized in the switch assembly of the present invention.

FIG. 5 is a schematic diagram illustrating the motor control circuitrywhich is controlled by the touch buttons.

DESCRIPTION OF PREFERRED EMBODIMENT Referring now to the drawing, itwill first of all be understood that the switch assembly of the presentinvention is especially adapted to control the speed of a universalmotor; more particularly, a motor having the purpose of driving ablender cutting device. Accordingly, there will be seen in FIG. 1, ablender 10 comprising a housing 20 which includes a console 22 dividedinto sections. The large middle section includes a plurality of touchbuttons 24. The touch buttons are selectively actuated for the purposeof controlling the speed of the universal motor, not seen in FIG. 1, butshown in the circuit diagram of FIG. 4. The motor 30 is therein shownschematically since the series connecting field windings and armature ofsaid motor are conventional. The motor 30 has its speed determined bythe control device, also seen in FIG. 4, in the form of a siliconcontrolled rectifier 32 which is connected in series with the motor. Forconvenience, the control circuitry which affects the triggering of thesilicon controlled rectifier 32 is generally designated 34 and includesthe aforesaid touch buttons 24.

Each of the touch buttons 24 is of the particular constructionillustrated in FIGS. 2 and 4. Thus, each of the touch buttons comprisesa plastic cap 24A, including an integral flange 24B, and an elongatedstud 24C which is adapted to pass through one of the suitable openings38 in a printed circuit board. The plastic cap 24A projects through oneof the recesses 42 which is formed in a plastic member constituting theupper wall 44 of the console 22. The circuit board 40 is designed tocontain the various components of the circuit diagram of FIG. 4 and tobe suitably secured to the console in spaced relationship to the upperwall 44. By reason of the biasing provided by a spring 46, the flange243 formed at the periphery of the cap 24A is forced against the innersurface of wall 44. A bell-shaped, movable contact 48 surrounds the stud24C and is operative to bridge the spaced contacts 50 on the circuitboard 40, thereby completing a selected individual path, as will beappreciated by reference to the schematic diagram of FIG. 6, whereinlike parts are shown schematically.

It will be particularly noted in FIG. 4 that the clearance between themovable contact 48 and the fixed contacts 50 on the circuit board isextremely slight,

being of the order of 0.030 inches. Also it should be noted that theupper surface of the cap 24A has a convex shape and furthermore that theprojection of the cap 24A above the recess 42 in the upper wall is .very

slight, being of the order of 0.015 inches. Accordingly, I

it will be appreciated that only very light touching, and concomitantlyvery slight travel, of the touch buttons 24 is necessary in order toeffectuate contact closure. Moreover, because of the particularconstruction, finger actuation over a reasonably broad area is capableof producing such contact closure. This latter point will become moreapparent as the description proceeds.

The indicia-bearing, switch actuating means of the switch assembly ofthe present invention may be appreciated by reference to FIG. 3. Thisswitch actuating means takes the form of a cover plate 60 in one piece,although such a means could be formed of several lateral pieces orsections. Essentially, the periphery of the cover plate 60 is adapted tofit around the timer control 26 and the master control switch 28, beingprovided with suitable openings for this purpose. The central section ofthe plate designated 62, which is indicated in FIG. 3 by phantom lines,is adapted to fit over and correspond with the array of push-buttons ortouchbuttons 24. The size of this array of touch-buttons is, in theexample illustrated, about 3.5 inches long by about 2 inches wide.

The cover plate 60 is preferably formed as a thin laminate comprisingtwo layers of plastic material. It has been found that polyester is themost suitable plastic material, being able to fulfill the requirementsof extreme flexibility and resilience, while providing strength anddurability for the cover plate. Accordingly, an exemplary cover plate 60has been fabricated of a 13 mil Mylar vinyl base layer, with a 4 milclear Mylar cap, or upper layer, (No. 371 acrylic). Approximately 4 milof permanently pressure-sensitive adhesive is provided at the surfacewhich contacts the wall 44, except that no adhesive is used within thesection 62. Because of the great flexibility and resilience possessed bythe cover plate, only the slightest pressure on the section 62 isrequired to bend or distort a selected areas so as to cause depressionof the corresponding touchbutton 24 that lies beneath a particularindicia at that area representing a condition to be realized. Moreover,the flexure of the selected area on said cover plate is such that thebending or distorting effect produced therein is localized so as tocause depression of only the selected touch-button, and not of anyadjacent button.

it will be especially appreciated that the switch assembly of thepresent invention is adapted to be utilized as part of a touch buttoncontrol system as described in copending US. Pat. application Ser. No.380,416 assigned to the assignee of the present invention. For acomplete description of that system reference may be made to thatcopending application; however, since the switch assembly of the instantinvention can be understood independently of the structural details ofthe system, only a brief description of the operation of the system willbe provided here.

Actuation of a particular touch-button 24 resultsin applying a charge tocapacitor 70 so as to produce a voltage value thereon corresponding withthe voltage value picked off from the potentiometer 61 by actuation ofthat particular button. Accordingly, a bias voltage of sufficientmagnitude is impressed on the base of transistor 78 by, way of theresistor 74 to turn on tran-, sistor 78. The particular voltage selectedby the touch button acts to produce a particular output impedance oftransistor 78, which forms part of the RC network 79, such thatcapacitor therein is charged positively at a predetermined rate duringthe positive half wave of the voltage supplied from the 115 volt ACsource. The degree of conductance of transistor 78 determines thischarging rate; consequently, the degree of conductance determines thepoint during the, positive half wave at which the capacitor 80 will havecharged sufficiently to produce a voltage effective to cause the Zenerdiode 84 to break down. Breakdown of the Zener diode results intriggering the SCR device 32 to a state of complete conduction, therebyallowing current to flow through the motor 30. The triggering of device32 is a consequenceof the discharge of capacitor 80 into the gateelectrode and shunting resistance 86.

It will be appreciated that the higher the value of the bias voltageapplied at the input of transistor 78, the greater will be the outputconductance thereof; hence, the faster the charging rate and the earlierin the positive half wave that the device 32 will become conductive. Asa consequence of a faster charging rate, the higher will be the speedobtained for motor 30. it will further be understood by those skilled inthe art that, because of the isolation provided by the transistor 78,there will be no significant leakage of charge from capacitor 70 as itfunctions for memory purposes. Therefore, the bias voltage at the inputof transistor 78 remains established until another speed choice iseffected by subsequent actuation of a different touch buttom from theprevious one being remembered.

The mode of operation just described above is conveniently called theManual Mode; that is, a mode which does not involve use of the timer 26.Such timer permits automatic operation whereby the blender isautomatically shut down after the time period set by the timer hasexpired. As in the aforesaid Manual Mode, when the Timing Mode isdesired the unit is powered up in the same manner by moving the controlswitch 28 from the OFF to the ON position. The timer 26 is set to apredetermined position by turning dial 107 so as to affect timer control106. For example, let us say, the dial is set to the 30 second positionout of a total of perhaps 60 seconds. When the dial 107 is thus set, theswitch 110 is automatically opened thereby permitting charging of thecapacitor 114. The charging rate is selected by reason of the positionof the movable arm 1 12 on the potentiometer 108. As was the case beforein the Manual Mode, the motor speed is then selected by actuation of oneof the touch buttons 24. However, after a repertoire of functions hasbeen performed and the 30 seconds timing interval has expired, thecapacitor 114 will then have been charged to a point where it willproduce breakdown of the Zener diode 122 in the timer circuit 120. Thisresults in switching the transistor 124 to the conductive state suchthat a substantial short circuit is provided across the capacitor 70whereby. the capacitor 70 is substantially discharged. Asa consequence,there is no longer sufficient bias at the baseof transistor 78 and themotor 30 will stop. However, the neon lamp 102 will remain energizeduntil control switch 28 is moved to the OFF position.

lt will'be appreciated that once transistor 124 has beenturne'don, dueto the breakdown of Zener diode 122, it'will remain on due to the DC.bias then applied to the input of transistor 124 by reason of theconnection from point C through resistor 113, potentiometer 108, and theconductive diode 122. At the same time, the transistor 128, coupled totransistor 124, is also turned on and is likewise kept on. The functionof transistor 128 is to ensure that when the timing period set for thetimer circuit has terminated, there will be no possibility of a spuriousbias condition existing sufficient to turn on motor 30. This ispositively ensured because of the connection from the top of capacitor76 to the collector of transistor 128.

The transistors 124 and 128 remain on together only until either poweris switched off by reason of actuation of master control switch 28 orthe timer 26 is returned to the normal position, at which point switch110 is closed.

A further mode of operation is provided for the blender by an additionalposition for the control switch 28: namely, the Pulse position, which isthe lowest position for the switch. In this position, because of thestrapping connection between fixed contacts 94A and 94B, and thebridging of contacts 94B and 968 by movable contact 988, the neon lamp102 will again be ON and power is likewise supplied to the motor 30.However, the capacitor 70 is now out of the circuit because the line 73is now riot connected through the switch contacts 90A and 92A. Sincecapacitor 70 cannot therefore be charged, the motor 30 will only operatewhen a predetermined touch button is held down and will continue tooperate only when a button is so held. It will be noted that the contact96A is provided as part of the control switch assembly. This contactproduces, upon selection of the pulse mode of operation, shorting out ofcapacitor 1 l4, and hence removal of the change that may have beenstored therein. This is done in order to cancel and render ineffectiveany timer setting that that had been previously established.

Although a particular embodiment of the switch assembly of the presentinvention has been illustrated, it will be understood that the inventionis not limited to this particular embodiment. Moreover, it will beappreciated that the switch assembly is also useful in controllingswitch contacts which in turn would control parameters other than motorspeed. It will therefore be understood that many modifications of thepresent invention may be made by those skilled in the art..

What is claimed is:

l. A switch assembly, comprising:

a plurality of fixed and movable switch contacts having open and closedpositions; an array of separated, spring-biased, rigid touchbuttonsrespectively movably actuating the movable switch contacts to theirclosed positions with 5 respect to said fixed contacts;

a smooth surface, extremely flexible and resilient, in-

dicia-bearing cover plate, adapted to be contacted by a user, fittingover and contacting said array of touch-buttons so that flexure of apredetermined area on said cover plate operates selectively to depressone of said touch-buttons and to move a cor responding one of saidmovable contacts into its closed position;

a console having a wall provided with openings, said array oftouch-buttons extending respectively through said openings and slightlyabove said wall said cover plate bearing on said console wall.

2. The combination as defined in claim 1, in which each of saidtouch-buttons includes a cap having a convex upper surface.

3. The combination as defined in claim 1, further comprising a circuitboard, including said fixed contacts thereon, said fixed contacts beingadapted to be momentarily contacted respectively by said movable switchcontacts, each of said touch-buttons including a stud portion projectingthrough an opening in said circuit board. I

4. The combination as defined in claim 1, in which the slight extensionof said touch-buttons above the console wall is of the order of 0.015inches.

5. The combination as defined in claim 3, in which the clearance betweeneach of the said movable contacts and said respective fixed contacts isof the order of 0.030 inches.

6. The combination as defined in claim 1, in which said indicia-bearingcover plate is composed of a plastic material.

7. The combination as defined in claim 6, in which said cover plate is alaminate of two layers of plastic material.

8. The combination as defined in claim 6, in which said plastic materialis polyester.

9. The combination as defined in claim 1, in which said array oftouch-buttons is closely spaced in an area approximately 2 X 3.5 inches.

10. The combination as defined in claim 1, in which said cover plate isadhered to the console wall, except in the area occupied by saidtouch-buttons.

1. A switch assembly, comprising: a plurality of fixed and movableswitch contacts having open and closed positions; an array of separated,spring-biased, rigid touch-buttons respectively movably actuating themovable switch contacts to their closed positions with respect to saidfixed contacts; a smooth surface, extremely flexible and resilient,indiciabearing cover plate, adapted to be contacted by a user, fittingover and contacting said array of touch-buttons so that flexure of apredetermined area on said cover plate operates selectively to depressone of said touch-buttons and to move a corresponding one of saidmovable contacts into its closed position; a console having a wallprovided with openings, said array of touch-buttons extendingrespectively through said openings and slightly above said wall saidcover plate bearing on said console wall.
 2. The combination as definedin claim 1, in which each of said touch-buttons includes a cap having aconvex upper surface.
 3. The combination as defined in claim 1, furthercomprising a circuit board, including said fixed contacts thereon, saidfixed contacts being adapted to be momentarily contacted respectively bysaid movable switch contacts, each of said touch-buttons including astud portion projecting through an opening in said circuit board.
 4. Thecombination as defined in claim 1, in which the slight extension of saidtouch-buttons above the console wall is of the order of 0.015 inches. 5.The combination as defined in claim 3, in which the clearance betweeneach of the said movable contacts and said respective fixed contacts isof the order of 0.030 inches.
 6. The combination as defined in claim 1,in which said indicia-bearing cover plate is composed of a plasticmaterial.
 7. The combination as defined in claim 6, in which said coverplate is a laminate of two layers of plastic material.
 8. Thecombination as defined in claim 6, in which said plastic material ispolyester.
 9. The combination as defined in claim 1, in which said arrayof touch-buttons is closely spaced in an area approximately 2 X 3.5inches.
 10. The combination as defined in claim 1, in which said coverplate is adhered to the console wall, except in the area occupied bysaid touch-buttons.